Shake, Rattle... but no Roll

The largest earthquake in recorded history (see list HERE) occurred in Valdivia, Chile in 1960.  It measured 9.5 on the Moment Magnitude Scale and lasted an agonizing ten minutes.  It was so powerful that it generated a tsunami that devastated Hilo, Hawaii.  Estimates put the death toll as high as 6,000 and damage estimates (in today’s dollars) in the range of $3-6 Billion.

Columbian novelist Gabriel García Márquez  once wrote: “Chile has an earth tremor on the average of once every two days and a devastating earthquake every presidential term.” (from this article)  So obviously, the Chilean people are used to the ground shaking beneath their feet.

 

An 8.8 tremor in 2010 rattled the country for 3 minutes.  The quake and the resulting tsunami killed 500 people and wiped some coastal communities out to sea.  An 8.2 event in 2014 caused widespread damage, resulting in 6 deaths.  Chile’s most recent seismic event occurred just last week.  The September 16^th event measured 8.3.  Quake and tsunami damage in the region killed 14 and caused the evacuation of a million coastal residents.  Most have now returned to their homes.

But in terms of the devastation and catastrophic loss of life that seems to accompany earthquakes in other parts of the World, the question was asked by a number of news outlets:  Why have these latest Chilean earthquakes had a much smaller death toll than even the 2010 event?  I wondered the same thing. So I set out to find out why.

Pascale Bonnefoy and Patrick Lyons of the New York Times answered this question in a highly informative article published the day following the quake.  (Link HERE)  Their findings comprise an excellent summary of the kinds of preparations organizations, communities, states and nations can take to minimize the impact of otherwise disastrous events.  I’ve organized their text (below) under headers that highlight these findings:

LUCK

“The latest earthquake was not as powerful.  Though the earthquake on Wednesday was quite strong, at magnitude 8.3, it released only about a third of the energy of the magnitude 8.8 quake in 2010, one of the strongest recorded in modern times. (Magnitude is measured on a logarithmic scale.)”

This is definitely not something we can control, though to be able to predict an event would be extremely beneficial indeed.

LOCATION

“It affected a more focused area.  The 2010 quake struck off the central coast and directly affected large cities and populous areas, including resort areas crowded with vacationers. At least one-third of the country’s coastline suffered significant damage from the tsunami it created, and more minor damage was reported as far away as San Diego and Tokyo. Almost all of Chile lost power. By contrast, the latest quake and its tsunami have mainly affected a single, less densely populated region, Coquimbo.”

This isn’t necessarily a factor we can control, but it does perhaps demonstrate the value of site selection of major facilities, stronger building codes for coastal areas, and zoning that places less-inhabited, less vulnerable (e.g., industrial or agricultural) uses in areas prone to damage.  In some cases governments may have to make tough rebuilding decisions.

PREPARATION

“Coastal residents were better prepared.  Since the 2010 quake, there have been many earthquake drills and dry runs, and evacuation routes have been clearly marked up and down the coast. As a result, though the latest quake’s tsunami did extensive physical damage in several coastal cities and ports, very few people were in harm’s way when the waves hit. In 2014, when a magnitude-8.2 quake struck off northern Chile, Coastal areas were evacuated quickly and efficiently.”

WARNING SYSTEM

“In 2010, no tsunami alert was issued, and national leaders prematurely told the public that they could return to their homes. Residents in coastal areas knew to head for higher ground, but many visitors did not. Since then, the government has issued immediate preventive tsunami warnings and has been much more cautious about sounding the all-clear, as seen in the 2014 quake and again this week.”

STRONGER BUILDING CODES

“In poorer, developing countries like Haiti or Nepal, major quakes are often devastatingly deadly, with thousands of people killed by collapsing buildings, bridges and dams. It used to be that way in Chile, too, but decades of prosperity have raised construction standards, and the country has learned through hard experience to set and enforce stringent building and safety codes along the lines of those used in California. Because of this, Chile’s modern buildings tend to fare well in quakes, though historical structures and those in rural areas may still be vulnerable.”

Planner Kenneth Topping (link here) talks about an example from the other side of the world that underscores this point. He writes:  "Following the March 11, 2011, Mw 9.0 Great East Japan Tohoku earthquake and tsunami, 14,843 people were reported dead or missing in Miyagi Prefecture as of May 2011. Yet within the prefecture’s largest city of Sendai, population 1,045,903, the number of persons dead or missing was 882—a remarkably low figure for a large city struck by a great earthquake. This attests to the importance of Japan’s strict national building codes in saving lives."

EMERGENCY RESPONSE

“Since 2010, the National Seismic Center in Chile has been operating around the clock, as have many of the regional offices of the government’s national emergency bureau. More robust sea-level monitoring systems and better procedures to help coordinate the efforts of public and private agencies have also made a difference.”

These are very valuable lessons indeed.  The points made by Bonnefoy and Lyons comprise a useful check list of the primary components of a resilience plan.  Best of all, they illustrate how one country’s populace benefited from attention to key, critical preparations. 

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Photo Credit:  SBSTV (Australia)